This invention relates to eyeglasses and auxiliary lens attachment devices. More particularly, the present invention relates to an auxiliary lens attachment frame that magnetically and securely attaches the auxiliary lenses to the eyeglasses, is easy to install, and yet unobtrusive.
It is often desirable to change the amount or type of light blocked, i.e. filtered, by eyeglass lenses. The desire to alter the amount of light filtered by eyeglass lenses may be necessitated by medical concerns, performance benefits or mere aesthetic preferences. Light filtering lenses having different light filtering properties are desired by eyeglass wearers in a vast variety of activities. By way of example, these activities include target gun shooting, fishing, snow skiing, daytime driving and nighttime driving. Due to the variety of reasons requiring lenses of differing light filtering properties, there is no one lens that can accomplish all of the possible lens light filtering requirements. As an alternative to the costly option of purchasing numerous sets of eyeglasses each having lenses of differing light filtering characteristics, numerous solutions have been proposed in the past to accommodate the need to alter or change the light filtering properties of eyeglass lenses.
There are eyeglass lenses for which the amount of light filtered varies depending on the amount of ambient light the lens is exposed to. While this type of lens may seem to overcome the problems noted above, these types of lenses tend to be limited as far as the amount and/or type of light filtering provided by a given lens. Additionally, once a set of eyeglasses is manufactured with particular lenses having given light filtering properties, the light filtering characteristics of the lens is fixed.
Other prior art attempts at addressing the above mentioned problems involve attaching auxiliary frames having lenses of the desired light filtering characteristics to the frame of eyeglasses. This approach is appealing because the auxiliary lenses can be manufactured to have the exact light filtering characteristics desired to suit the medical condition, activity or aesthetic preference of the wearer.
In the past auxiliary lenses have been attached to the primary eyeglass frame via a number of means. Clips of various sizes and configurations have been employed to attach the auxiliary lenses to the primary eyeglass frame. Clip mounted auxiliary lens devices attached to a primary eyeglass frame detract from the aesthetic shape and beauty of the primary eyeglasses because clips are unattractive, obtrusive and are not a usual or customary part of eyeglasses. Also, in order to achieve any sufficient amount of holding power, the clips of the auxiliary lenses must physically fit tightly onto the primary eyeglass frame. The need for a tight mechanical fit between the auxiliary lens frame and the primary eyeglass frame necessarily means that stresses and forces must be exerted on the auxiliary lenses and/or the eyeglass frame to attach the auxiliary lenses to the primary eyeglass frame. The need to place the primary eyeglass frame and/or the auxiliary lens frame under additional forces in order to attach the two together can damage the primary eyeglass frame and/or the auxiliary lens frame. The mechanical fit of the auxiliary frame and the primary eyeglass frame also tends to lessen over time.
Another method of attaching auxiliary lenses to eyeglass frames involves providing both the auxiliary lens frame and the primary eyeglass frame with attached magnets that attract and hold the auxiliary lens frame and the primary eyeglass frame together. U.S. Pat. No. 5,416,537, incorporated herein by this reference, discloses an auxiliary lens frame that magnetically engages with the primary eyeglass frame. According to this frame, mating magnets are attached externally and/or are embedded into the face of the primary eyeglass frame. This configuration results in an unattractively altered primary eyeglass frame having visibly attached magnets and/or requires specialty manufactured primary eyeglass frames that are expensive to manufacture and altered in integrity. The auxiliary lenses are attached to the primary eyeglass frame simply by the magnetic forces of the oppositely opposed but attracting mating magnets. The auxiliary lens frame is prone to become disengaged from the primary eyeglass frame when engaged and worn during movement by the wearer since the magnetic attraction forces alone are not great enough to prevent disengagement.
Also, U.S. Pat. No. 5,568,207, incorporated herein by this reference, discloses auxiliary lenses that magnetically engage with the primary eyeglass frame, The magnetic components of the auxiliary lens are positioned in direct contact with the side and rear of the primary eyeglass lens rim. In this disclosure frame, the primary eyeglass frame's magnetic members only directly support the magnetic members of the auxiliary lenses from downward disengagement. The disclosed frame also discloses the extension of the auxiliary lens frame's magnet to fit over the side end-piece of the primary eyeglass frame for the purported purpose of preventing the downward disengagement of the auxiliary lens.